One friend of mine told me that drz 400 e with metal fuel tank has 49 hp, but in the net I see that there are drz 400 e with plastic fuel tank. It is obvious that I want to buy the version with the higher output like 48-49 hp, but it is very difficult to understand the hp of every each bike because here in Bulgaria everyone lies about the model and hp of the bike. May be if there is some platform where I can put the number of the engine to know for sure which type it is, it would be nice.

The E puts out around 50hp. The S and SM put out around 33hp. The S/SM have a different carb but the bigger issue is the PAIR vavle attached to it, 3mm smaller header & a much more restrictive slip on.
The conflictind information is on the cams and base gasket setup. Some are saying they are different. Others say they were different til a certain year then the S/SM & E core engine was essentially the same.